This invention relates to pressure sensing catheters of the type having a substantial length to be inserted into the human body to measure pressures therein. It finds its best potential use at this time in the measurement of pressure in the bladder and in the urethra and in measurement of intrauterine pressure in obstetrical procedures.
Catheters for these purposes are known. Some of them require the presence of an electrical current in the instrument within the human body and are therefore objectionable on that ground alone. All are sensitive to their angular orientation within the region being measured and therefore have certain latent uncertainties in their output. Others suffer from excessive cost due to their complexity. It should be recalled that these are small catheters. In general, the outer diameter of this basic catheter structure is only about 0.080 inches and it is necessary to keep the diameter of the instrument at its largest within about 0.150 inches. Thus, the device is quite small and is difficult to manufacture whatever its construction.
It is an object of this invention to utilize only light internally of the human body for sensing and to provide the catheter and its sensor in a form which is economically manufacturable.